Prognostic study, level III.

Acute pelvic pain in premenopausal women frequently poses a diagnostic dilemma. These patients may exhibit nonspecific signs and symptoms such as nausea, vomiting and leukocytosis. The cause of pelvic pain includes a myriad of diagnostic possibilities such as obstetric, gynecologic, urologic, gastrointestinal, and vascular etiologies. The choice of the imaging modality is usually determined by a suspected clinical differential diagnosis. Thus the patient should undergo careful evaluation and the suspected differential diagnosis should be narrowed before an optimal imaging modality is chosen. Transvaginal and transabdominal pelvic sonography is the modality of choice, to assess for pelvic pain, when an obstetric or gynecologic etiology is suspected and computed tomography is often more useful when gastrointestinal or genitourinary pathology is thought to be more likely. Magnetic resonance imaging, when available in the acute setting, is favored over computed tomography for assessing pregnant patients for nongynecologic etiologies owing to its lack of ionizing radiation.The American College of Radiology Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

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Imaging of the gallbladder has a key role in the examination of patients with abdominal pain-especially pain localized to the right upper quadrant. Pathologic conditions that affect the gallbladder include cholelithiasis and associated complications such as acute and chronic cholecystitis, choledocholithiasis, gallstone pancreatitis, and cancer. Modalities used to image the gallbladder include ultrasonography (US), computed tomography (CT), magnetic resonance (MR) imaging, and nuclear scintigraphy. US is the primary imaging modality used to evaluate entities suspected of being gallbladder disease, as it is both sensitive and specific for demonstrating gallstones, biliary duct dilatation, and inflammatory features. However, CT is often the first imaging examination performed in patients who present to the emergency department with acute abdominal pain. Because the CT appearance of gallstones is variable, depending on the composition of the stone, pattern of calcification, and presence of gas, gallstones and other gallbladder conditions can be difficult to detect at conventional multidetector CT, with which data are acquired by using a single x-ray energy spectrum. Dual-energy CT, with which one takes advantage of the material-dependent x-ray absorption behavior of concurrently acquired high- and low-kilovolt-peak data, can add value by increasing the conspicuity of noncalcified gallstones and improving the detection of acute cholecystitis and gallbladder malignancy. In addition, MR cholangiopancreatography can be helpful for assessing choledocholithiasis and complicated biliary duct disease. RSNA, 2018.

Low keV virtual monochromatic imaging increased conspicuity of noncalcified gallstones, improving their detectability.

The arterial phase of image acquisition improves detection of traumatic contained splenic vascular injuries and should be considered to optimize detection of splenic injuries in trauma with CT.

The purpose of this study is to evaluate the performance of a sequential multi-modality imaging algorithm for diagnosing acute appendicitis in pregnancy. This IRB-approved, HIPAA compliant study included 127 consecutive pregnant patients imaged for suspected appendicitis between October 2007 and May 2012; all patients initially underwent ultrasound (US) examination, followed by magnetic resonance imaging (MRI) if results of US were negative or equivocal. Computerized tomography (CT) was reserved for cases with inconclusive US and MRI results. The EMR was reviewed, recording results of imaging examinations and clinical outcomes. The diagnostic performance of this sequential multi-modality imaging algorithm was calculated with pathology correlation. Two (1.9 %) of the 127 US examinations reported suspected appendicitis; 125 (98.4 %) were inconclusive. Of the 125 patients with inconclusive US examinations, 103 underwent MRI, of which eight (6.2 %) demonstrated findings of acute appendicitis. Of the 103 patients that received MRI, nine (8.7 %) underwent CT. One patient had a CT performed directly after an inconclusive US exam. No additional cases of appendicitis were detected with CT. The sensitivity and specificity of US alone was 12.5 and 99.2 %, respectively; MRI was 100 and 93.6 %; the sequential multi-modality modality algorithm including US, CT, and MRI was 100 and 98.3 %. The diagnostic performance of this sequential multi-modality imaging algorithm for diagnosing acute appendicitis in pregnancy is high. Given the low yield of US, MRI should be considered the first-line imaging test. Although CT was employed in a small fraction of inconclusive MRI examinations, it still has a role in the diagnostic work-up of the pregnant patient with suspected appendicitis.